Abstract: This disclosure provides an extravascular ICD system and method for defibrillating a heart of a patient. The extravascular ICD system includes multiple extravascular electrical stimulation leads or lead segments located in close proximity to one another and having respective defibrillation electrodes. The ICD system utilizes the multiple defibrillation electrodes to form an extravascular electrode vector that may result a reduction in the shock impedance and/or a reduction in the DFT compared to extravascular ICD systems that include only a single extravascular defibrillation electrode. An ICD of the system may, for example, deliver a defibrillation shock using an electrode vector in which a first polarity of the electrode vector is formed by electrically coupling first and second defibrillation electrodes of first and second leads, respectively, to the therapy circuitry and a second polarity of the electrode vector is formed by electrically coupling a housing of the ICD to the therapy circuitry.

Abstract: An implantable cardioverter defibrillator (ICD) configured to transmit a tissue conduction communication (TCC) signal includes a TCC transmitter module configured to generate the TCC signal and transmit the TCC signal via a plurality of electrodes. The TCC signal comprises a biphasic signal having an amplitude and a frequency, wherein at least one of the amplitude and the frequency are configured to avoid stimulation of tissue of the patient. The TCC transmitter module comprises protection circuitry coupled between a current source and the plurality of electrodes, wherein the protection circuitry is configured to protect the signal generator from an external anti-tachyarrhythmia shock delivered to the patient.

Abstract: A medical device for sensing cardiac events that includes a plurality of light sources capable of emitting light at a plurality of wavelengths, and a detector to detect the emitted light. A processor determines a plurality of light measurements in response to the emitted light detected by the detector, updates, for each of the plurality of wavelengths, a first normalization coefficient and a second normalization coefficient in response to the detected emitted light, and adjusts the determined plurality of light measurements in response to the first normalization coefficient and the second normalization coefficient.

Abstract: Communication power in a medical device system is managed by providing power from a power supply to a communication circuit in a sensing device according to a first communication wake up mode set for a first time period and according to a second communication wake up mode set for a second time period. The second communication wake-up mode is established by a second device.

Abstract: A rechargeable cell of an implantable medical device is recharged by an external charging unit that includes a transmitting coil configured to emit an electromagnetic field and a near-field focusing plate having a subwavelength structure pattern that focuses the emitted electromagnetic field to a focal pattern. The implantable medical device includes a housing having a window of an electromagnetically transparent material and a receiving coil enclosed by the housing. The receiving coil extends adjacent to and is aligned with the window. The rechargeable cell is enclosed by the housing and is configured to be charged by current induced in the receiving coil when the receiving coil is exposed to the focal pattern. In some examples, the near-field focusing plate is configured to produce the focal pattern to have a size that is less than an outer dimension of the window and a focal length from the near-field focusing plate that at least reaches the window.

Abstract: A medical device system is configured to sense a physiological signal by a first device and generate a control signal by the first device in response to the physiological signal. An acoustical emitting device is controlled by the first device to emit an acoustical trigger signal in response to the control signal. A second device detects the acoustical trigger signal and delivers an automatic therapy to a patient in response to detecting the acoustical trigger signal.

Abstract: An implantable medical device comprises a communication module that comprises at least one of a receiver module and a transmitter module. The receiver module is configured to both receive from an antenna and demodulate an RF telemetry signal, and receive from a plurality of electrodes and demodulate a tissue conduction communication (TCC) signal. The transmitter module is configured to modulate and transmit both an RF telemetry signal via the antenna and a TCC signal via the plurality of electrodes. The RF telemetry signal and the TCC signal are both within a predetermined band for RF telemetry communication. In some examples, the IMD comprises a switching module configured to selectively couple one of the plurality of electrodes and the antenna to the receiver module or transmitter module.

Abstract: An implantable cardioverter defibrillator (ICD) configured to transmit a tissue conduction communication (TCC) signal includes a TCC transmitter module configured to generate the TCC signal and transmit the TCC signal via a plurality of electrodes. The TCC signal comprises a biphasic signal having an amplitude and a frequency, wherein at least one of the amplitude and the frequency are configured to avoid stimulation of tissue of the patient. The TCC transmitter module comprises protection circuitry coupled between a current source and the plurality of electrodes, wherein the protection circuitry is configured to protect the signal generator from an external anti-tachyarrhythmia shock delivered to the patient.

Abstract: This disclosure provides an extravascular ICD system and method for defibrillating a heart of a patient. The extravascular ICD system includes multiple extravascular electrical stimulation leads or lead segments located in close proximity to one another and having respective defibrillation electrodes. The ICD system utilizes the multiple defibrillation electrodes to form an extravascular electrode vector that may result a reduction in the shock impedance and/or a reduction in the DFT compared to extravascular ICD systems that include only a single extravascular defibrillation electrode. An ICD of the system may, for example, deliver a defibrillation shock using an electrode vector in which a first polarity of the electrode vector is formed by electrically coupling first and second defibrillation electrodes of first and second leads, respectively, to the therapy circuitry and a second polarity of the electrode vector is formed by electrically coupling a housing of the ICD to the therapy circuitry.

Abstract: A system and method for identifying the location of a medical device within a patient's body may be used to localize the fossa ovalis for trans-septal procedures. The systems and methods measure light reflected by tissues encountered by an optical array. An optical array detects characteristic wavelengths of tissues that are different distances from the optical array. The reflectance of different wavelengths of light at different distances from an optical array may be used to identify the types of tissue encountered, including oxygenated blood in the left atrium as detected from the right atrium through the fossa ovalis.

Abstract: A medical device system is configured to sense a physiological signal by a first device and generate a control signal by the first device in response to the physiological signal. An optical transducer is controlled by the first device to emit an optical trigger signal in response to the control signal. A second device receives the optical trigger signal and delivers an automatic therapy to a patient in response to detecting the optical trigger signal.

Abstract: A medical device system is configured to sense a physiological signal by a first device and generate a control signal by the first device in response to the physiological signal. An acoustical emitting device is controlled by the first device to emit an acoustical trigger signal in response to the control signal. A second device detects the acoustical trigger signal and delivers an automatic therapy to a patient in response to detecting the acoustical trigger signal.

Abstract: A medical device system is configured to sense physiological events by a first device and control a transducer to emit trigger signals in response to the sensed physiological events. A second device detects the trigger signals and delivers therapeutic stimulation pulses in response to the trigger signals. The therapeutic stimulation pulses have a combined total time duration over the sensed physiological events that is greater than the combined total time duration of the trigger signals.

Abstract: An implantable medical device for detecting and treating an arrhythmia includes an optical sensor adapted for positioning adjacent to a blood-perfused tissue volume. In one embodiment for controlling arrhythmia therapies delivered by the device, the optical sensor is controlled to emit light in response to detecting an arrhythmia, detect light scattered by the volume of blood perfused tissue including measuring an optical sensor output signal corresponding to the intensity of scattered light for at least four spaced-apart wavelengths, and compute a volume-independent measure of tissue oxygen saturation from the detected light. The hemodynamic status of the arrhythmia is detected in response to the measure of tissue oxygen saturation.

Abstract: Implantable systems and methods (e.g., using an implantable medical device) for measuring distance including a transmit/receive acoustic transducer implantable at a first location for transmitting and receiving acoustic signals, an echo acoustic transducer implantable at a second location for receiving the acoustic signal from the transmit/receive acoustic transducer and in response thereto transmitting a return echo signal to be received by the transmit/receive acoustic sensor, and a controller to control transmission of the acoustic signal from the transmit/receive acoustic transducer at a transmit time and determine a receive time corresponding to the time the transmit/receive acoustic transducer receives the return echo signal. The distance between the transmit/receive acoustic transducer and the echo acoustic transducer is determined as a function of the transmit time and the receive time.

Abstract: A method and medical device for detecting signals that detects emitted light scattered by a volume of tissue delivered along a first pathway at a plurality of wavelengths to generate corresponding first detected light intensity output signals, detects emitted light scattered by the volume of tissue delivered along a second pathway different from the first pathway at a plurality of wavelengths to generate corresponding second detected light intensity output signals, determines whether a difference between the emitted light detected along the first pathway and the emitted light detected along the second pathway is greater than a predetermined threshold, and alters sensing by the device in response to the determining whether a difference is greater than the predetermined threshold.

Abstract: An implantable medical device lead having a flow measurement sensor mounted thereon is provided with a capsule mounted proximate to the sensor. The capsule is used to house electrical circuitry corresponding to the sensor in order to prevent impedance on conductors of the lead, which gradually decreases over chronic periods, from directly affecting signal transmission between the sensor and the electrical circuitry. The electrical circuitry includes a charge amplifier used for processing signals from the sensor. In some cases, the amplifier can be initially calibrated and periodically tuned so as to have consistent functioning with the sensor over chronic periods.

Abstract: A system and method for identifying the location of a medical device within a patient's body may be used to localize the fossa ovalis for trans-septal procedures. The systems and methods measure light reflected by tissues encountered by an optical array. An optical array detects characteristic wavelengths of tissues that are different distances from the optical array. The reflectance of different wavelengths of light at different distances from an optical array may be used to identify the types of tissue encountered, including oxygenated blood in the left atrium as detected from the right atrium through the fossa ovalis.

Abstract: A system and method are described for testing communication through a patient during implantation using telemetry coupling electrodes on a delivery catheter. In one example, at least two telemetry coupling electrodes may be placed on or within a delivery catheter to test conductive communication with external body electrodes during implantation. In some instances, the telemetry coupling electrodes of the delivery catheter may approximate the spacing of telemetry electrodes on an IMD. In this manner, testing conductively coupled communication with telemetry coupling electrodes of the catheter may be used to mimic the telemetry electrodes on the IMD and determine a target position and/or orientation of an electrode or electrodes of the IMD for successful conductive communication through the body.

Abstract: Systems, apparatus and methods for extension of longevity of implantable medical devices (IMDs) are provided. An apparatus includes a battery, a first communication component configured to provide a first communication type and to be powered by the battery, a second communication component configured to provide a second communication type, and a processor configured to switch on the first communication component or the second communication component to perform communication based, at least, on a defined condition being satisfied. In one embodiment, the first component is a radio frequency (RF) component and the second component is a component that requires less battery power than the RF component. The second component can include a component configured to perform communication based on inductive coupling or based on tissue conductance communication.